John Howard Northrop

John Howard Northrop was born on July 5, 1891, in Yonkers, New York. His father John Isaiah Northrop, a tutor in the zoology department at Columbia University was fatally injured in an explosion and fire at the zoology museum shortly before his birth. His mother, Alice Rich Northrop, was a botanist and naturalist and helped introduce nature studies into the curriculum of the New York City Schools.

Northrop excelled in chemistry and mathematics in the public schools of Yonkers, New York. Northrop attended Columbia University, studying chemistry and zoology, and was an outstanding member of the rifle and fencing teams, graduating with a B.S. in 1912. He continued at Columbia, earning a M.A. in 1913 and his pH.D. in 1915, completing a thesis on "The Organic Phosphoric Acid of Starch".

After finishing his doctorate, Northrop accepted an offer to work under Jaques Loeb at the Rockefeller Institute. He became an associate a the institute a year later and with the exception of a year spent as a Captain in the Chemical War Service (1917-1918) he remained at the institute becoming an associate member in 1920, a member in 1924. In 1949 he was appointed professor of bacteriology at the University of California and was later appointed professor of biophysics.

Northrop's work at Columbia concerned carbohydrates. Later, working under Loeb, he did research on Drosophilia, examining the relationship between environmental factors and heredity. During World War I, Northrop worked on ways of producing chemicals that were in short supply including acetone. In 1920 Northrop isolated pepsin using a method previously described by Cornelius Pekelharing, but was unable to crystallize it. When in 1926 James B. Sumner crystallized urease, Northrop took another look at the problem. In 1929 Northrop was able to crystallize pepsin and after numerous attempts to separate the enzyme activity from the protein, he was able to conclude that enzymes are proteins. At the time there was doubt about the nature of enzymes, and it was Northrop's work that was able to conclusivley demonstrate the protein nature of enzymes.

Enzymes are the catalysts that allow chemical reactions to take place in biological systems. Pepsin is a digestive enzyme that breaks down proteins into amino acids. Pepsin is secreted by the chief cells of the stomach in an inactive form called a zymogen. Hydrochloric acid, secreted by the parietal cells of the stomach cause the inactive pepsin (called pepsinogen) to cleave itself, leaving the active form of the enzyme.

Northrop is the author of Crystaline Enzymes published in 1939 and was the editor of the Journal of General Physiology for a number of years. In 1949 Northrop, along with Sumner, were awarded the Nobel Prize for Chemistry for their work demonstrating the protein nature of enzymes. Other awards Northrop has won include the Stevens Prize (from Columbia) in 1931, the Chandler Medal in 1936, the Elliot Medal in 1939 and the Alex Hamilton Medal in 1961. He also has honorary doctorates from the Universities of Harvard, Columbia, Rutgers and Yale.

Northrop died on May 27, 1987..


References:

Herriott, Roger M.; "John Howard Northrop"; Journal of General Physiology (1981) 77:597-599

Herriott, Roger M.; "John Howard Northrop" in Biographical Memiors, Vol. 63; National Academy Press; 1994

John H. Northrop, Nobel Biography